1. Field of the Invention
The present invention relates to a tank for a fluid system and more particularly to such a tank which is operable in conjunction with a fluid system to disseminate substances to fluid within the system during operation thereof and to prevent dissemination of the substances to fluid within the system when the system is inoperative.
2. Background of the Invention
It has been known to use a variety of types of devices to disseminate substances to a fluid stream in a multitude of areas of use. For example, it has been known to use sprinkler systems to dispense insecticides, fungicides, herbicides, nutrients, and the like through sprinkler systems. The applicant's U.S. Pat. No. 3,833,177 relates to a fluid disseminating device useful in a host of areas of particular use including the dispensing of such substances through a sprinkler system.
Incident to the dispensing of substances to a fluid stream, is the problem of controlling the period during which such substances are dispensed. It may be desired that the substance be dispensed in a single application wherein the fluid system is operated until all of the substance has been admitted to the fluid stream. However, in many instances this is not desirable and in still other cases it is impractical or impossible to do so.
For example, in the case of a lawn sprinkling system, all of the substance may not have been admitted to the fluid stream before it becomes necessary to turn the sprinkler system off to avoid waste as a result of run off from the lawn area. In other instances, where automatic timers are employed, the sprinkler system will be actuated at odd hours for fixed periods of time. Where the period of operation is not long enough completely to dispense the substance into the fluid stream, the balance of the substance may be wasted by discharge into the system after shut off. Even where such prior art devices have valves or other such controls for retaining the unused substance for later use, it may nonetheless be inconvenient if not impossible to operate such controls at the required time.
A still further problem incident to the use of disseminating devices, particularly where an automatic sprinkler system is involved, is the risk that the concentrated substance will be drawn backward through the fluid system and into the main fluid system by a syphoning action thus contaminating the main water supply and creating a hazardous condition. While city and/or county codes frequently require use of anti-syphon valves to prevent such a hazard, it is known that many, if not most, residences do not have such valves.
Therefore, it has long been known that it would be desirable to have a tank for a fluid system which has the capability for automatically dispensing substances to a fluid stream at a rate as controlled by the operator and which operates dependably and fully automatically to dispense such substances to the fluid stream only during operation of that fluid system preventing loss of the unused portion of the substance and precluding the creation of a hazardous condition.